Vehicle impact mitigation systems were developed to assist in reducing the intrusion of other vehicles and/or unwanted vehicle components into the passenger cabin of the vehicle during crash. Contemporary vehicles include front, side and overhead crash protection systems. Severe front impact situations can lead to the engine and its components intruding the passenger compartment. Past crash protection systems have included various designs that are inferior to the present invention.
For example, traditionally the front end structure of the vehicle consists of a bumper module, side rail and upper side rail (or “shotgun”). The side rail provides the primary energy absorption for the front end structure often absorbing as much as 80% of the impact energy. Accordingly, the length of the side rail is directly related to its energy absorption capabilities. The longer the side rail, the more energy it can absorb. In vehicles having a short front overhang, however, the crushable length of the side rail can be significantly shortened.
Some modern vehicles have sought to increase the length of the side rail in impact scenarios to provide additional crash space, as needed, during a crash. While the existing extendable rails and bumpers have provided flexibility in the design of the front end structure of these vehicles, the means of extending these rails can be improved. Some vehicles utilize a pyrotechnic system to deploy the bumper. However, the Applicant has found that these systems can cause heat damage during deployment and are not designed for multiple usages.
Other systems utilize electric motors to extend the front end structure, such as U.S. Pat. No. 6,773,044 titled “Active Vehicle Front Structure for Energy Management” to Schambre et al. Such electric motor based systems are slower than pyrotechnic systems and typically require more time than that which is desirable for deployment. To compensate, electric motor based systems generally extend the front end structure during regular driving speeds and retract the front end when the engine is stopped. This alters the look of the vehicle during normal driving conditions and is very undesirable from a styling point-of-view. In the alternative, some electric motor based systems rely on pre-crash sensing data for deployment but typically these systems do not respond as quickly as is desired. Where more powerful motors are utilized to expedite deployment, the size of the motor can present significant packaging and weight issues for the vehicle.
Additionally, once deployed the front module can be reinforced or locked into place using a locking feature. One locking feature is disclosed in U.S. Pat. No. 6,019,419 titled “Vehicle Rail Crush Control System and Method” to Browne et al. Disclosed therein are circumferentially-spaced, rotatable wedge members that move radially outward by actuation to lock the extended bumper in place. This design requires a rotatable arm for the wedges and multiple points of rotation for each wedge. Though this design reinforces the front module in the extended position, this design presents a more costly and unnecessarily complicated approach to locking the front module.
Therefore, it is desirable to provide a vehicle impact mitigation system with a rapidly deployable front end module. It would be beneficial to have a system that utilizes a mechanical deployment means that is resettable. Moreover, it is desirable to have a more cost effective locking mechanism for the system to secure the front module in the extended position after deployment.